二维晶体MXene的制备与研究进展

MXene是由MAX相材料制得的一种金属碳化物和碳氮化物的新型二维晶体。化学式为Mn+1Xn,其中n=1、2、3。M代表Ti、Sr、V、Cr、HF等过渡金属,X代表C或者N。MXene具有丰富的化学性质:良好的导电性、磁性和透光性等性能,目前在催化化学和电化学能量存储方面展现出非常好的应用前景。介绍了MXene材料制备及应用方面的研究进展,并对该材料的应用前景和未来发展作出展望。     

MXene/PANI复合材料的制备及其超电性能研究

本研究以MAXene(Ti_3AlC_2)刻蚀和剥离得到的MXene(Ti_3C_2)为基底,在酸性条件下将苯胺单体负载到MXene上制备MXene/PANI复合材料。利用场发射扫描电镜(SEM)、X射线衍射(XRD)对材料进行表征,在1 M H_2SO_4电解液中,对合成的复合材料进行电化学性能测试。结果表明,该种方法可成功制备MXene/PANI复合材料,在电流密度为0.5 A·g~(-1)时,复合材料比电容达到256.6 F·g~(-1),优异的电化学性能使得该材料可作为一种理想的超级电容器电极材料。     

MXene在电储能领域的研究进展

近年来，过渡金属碳或氮化物MXene一经问世，就引起广泛研究。因其具有独特的物理化学性质，MXene及其复合材料在储能、催化、传感、电磁屏蔽领域存在潜在价值。MXene在锂离子电池、钠离子电池等二次电池和超级电容器的应用中表现出优越的电化学性能，有广阔的应用前景。文中列举了目前广泛使用的磷酸铁锂电池的工作原理。综述了MXene及其复合材料在电储能领域的研究进展，对MXene材料及MXene基复合材料在电储能领域的研究做出展望。     

二维晶体Ti3C2Tx MXene发射与屏蔽电磁波的研究进展

MXene是一种新型二维材料,通过剥离层状陶瓷MAX相而制备.Ti3C2Tx MXene 是第一种制备的MXene,也是应用最广泛的MXene.Ti3C2Tx MXene具有良好亲水性,可以分散在水中制备成薄膜.同时具有良好导电性,具有叠层结构,电磁波可以在材料内部的界面多次反射.因为独特的性能与结构,MXene可以作...     

二维MXenes的制备及催化产氢性能研究进展

过渡金属碳化物、氮化物MXenes是一类新型的二维材料,通式为MnXn-1Tx(n=2～5).MXenes具备独特性能,在催化、储能、吸附等领域受到广泛关注.综述了MXenes的发展进程,不同的MXenes制备方法对MXenes结构、性能和表面官能团的影响以及MXenes复合材料在催化领域的应用研究现状,关于MXene...     

二维层状Ti基MXene的电化学性能研究进展

MXene是一种新型前过渡族金属碳(氮)化物,因其独特的二维层状结构,良好的导电性和稳定性,以及层间可以容纳离子和分子的特性,使其在储能领域受到广泛关注。通过插层处理,与高分子材料、金属氧化物等复合可以改善MXene的电化学性能。综述了Ti基MXene及其复合材料在锂离子电池和超级电容器方面的理论研究和应用研究现状。     

新型二维材料MXene吸附重金属的研究进展

近年来,新型纳米材料MXene因独特的形态及化学结构受到了广泛关注。MXene是一个二维过渡金属碳化物和氮化物的家族,通常由刻蚀前驱体MAX层状金属陶瓷相合成。通过刻蚀较弱的A原子将MAX上下两层抽出,即可得到层状的MXene材料。该类材料具有类石墨烯二维层状结构、较大的比表面积、良好的亲水性能、优异的稳定性和导电性,...     

不同形态MOF-5为前驱体合成多孔碳材料及其超级电容特性

以不同形态的MOF-5为前驱体,直接碳化合成多孔碳电极材料,用X射线衍射(XRD)、透射扫描电镜(SEM)对样品的形貌和结构进行表征,然后再把该样品用作超级电容器的电级材料,利用循环伏安法、恒流充放电对电容器电化学性能进行测试。结果表明,其中一种形式材料要比另一种形式材料的比表面积大,而且孔结构比较丰富,作为超级电容器的电极材料具有良好的电化学性能,在5A/g充放电流下,电容可达125F/g。     

普鲁士蓝镶嵌聚吡咯薄膜电极的制备及其电化学电容性质的研究

为提高聚吡咯电极材料电化学性能，研制出一种普鲁士蓝(PB)镶嵌聚吡咯(PPy)薄膜电化学电容器电极。采用化学沉淀法结合气相聚合(VPP)法将同步合成的PB引入PPy薄膜中，制备了自支撑聚吡咯/普鲁士蓝(PPy/PB)复合电极材料。利用扫描电子显微镜、拉曼光谱、X射线粉末衍射技术等对复合材料的形貌及结构进行表征。在三电极体系和对称超级电容器中研究PPy/PB复合材料的电化学表现，研究结果表明，PPy/PB复合材料组装的超级电容器比电容高达447.6 F/g。不同电流密度下充放电性能研究表明，电流密度从1.0 A/g增大到10.0 A/g时，PPy/PB比容量保持率为70.8%,具有优异的倍率性能。通过4 000次恒流充放电后PPy/PB电容保持率为76.9%,高于纯PPy电极材料，显示出较好的电容性能。     

一步法合成二维Ti3C2及其电化学性能研究

二维过渡金属碳/氮化物（MXene）是一种新型二维材料,可通过从MAX相前体中选择性刻蚀 A 原子层获得。在传统制备MXene的方法中,常用的刻蚀剂是氢氟酸。然而高浓度氢氟酸的使用,不可避免会带来安全问题,甚至破坏MXene的晶体结构,从而限制本征物理化学性能。从典型的碳化物前体Ti₃AlC₂出发,使用 NH₄BF₄作为刻蚀剂,有效降低体系中酸的使用量;在反应过程中,刻蚀 A 层的同时,\mathrm{N}{\mathrm{H}}_{\mathrm{4}}^{+}进入堆垛层间,扩大层间距,弱化层间作用力。因此,仅通过简单手摇就可以实现高效剥离,得到具有完整晶体结构的二维Ti₃C₂。进一步测试了Ti₃C₂的电化学性能,结果显示,所得的Ti₃C₂具有优异的性能（扫描速率为5 mV?s^-1时为503 F?g^-1）和循环稳定性（在5 A?g^-1下循环10⁴次后电容保持率为95.8%）。本文为Ti₃C₂纳米片的合成及应用提供了新的思路。     

Synthesis and properties of 2D-titanium carbide MXene sheets towards electrochemical energy storage applications

The cult MAX phases and MXenes has been a point of an attractive new family of 2D materials for diverse applications. In the present work, titanium carbide MXene sheets have been prepared by etching aluminium from titanium aluminium carbide MAX phase. The sample was investigated by X-Ray diffraction, FESEM, TEM and RAMAN analysis. XRD analysis revealed that the synthesized MXenes were formed in hexagonal crystal system and FE-SEM analysis showed that titanium carbide sheets were exfoliated. Raman analysis showed that the lower modes, which correspond to the “A” phase, disappeared due to the removal of aluminium. The electrochemical performance of the synthesized MXenes towards supercapacitor applications was further investigated using various electrochemical techniques like cyclic voltammetry (CV), charge-discharge and impedance analysis. Results showed that the new material showed an excellent performance in charge storage applications.     

Enhancing the electrochemical performance of d-Mo2CTx MXene in lithium-ion batteries and supercapacitors by sulfur decoration

With the development of the energy industry, electrochemical energy storage technology is increasingly involved in developing innovations in the field. The materials of the electrode have a significant influence on the performance of energy storage devices. For this purpose, two-dimensional MXene with excellent electrical conductivity, mechanical strength, and a variety of possible surface-active terminations are attracting much attention. In the present work, S-decorated d-Mo₂CT_x (d-Mo₂CT_x--S) is designed. The first-principles calculations reveal that it may possess good energy storage characteristics. Due to the decoration with S, unique morphology and structure are obtained, conferring stability, optimized Li⁺ storage, improved charge transport, and lithium-ion adsorption capabilities. Compared with d-Mo₂CT_x, d-Mo₂CT_x--S exhibits higher discharge capacity (623 mAh g⁻¹ at 1 A g⁻¹) as lithium-ion electrode material and higher specific capacitance (561 F g⁻¹ at 1 A g⁻¹). As a supercapacitor, the material also shows excellent cyclic stability (20,000 charge-discharge cycles). This work may inspire the exploration of other MXene and new surface functionalization methods to improve the performance of MXene as electrode materials for new energy devices.     

Lamellar MXene: A novel 2D nanomaterial for electrochemical sensors

MXenes, as recently emerging lamellar two-dimensional (2D) materials of transition metal carbides and/or nitrides, have attracted intensive attention for various applications in sensors, catalysis, energy storage, and biomedicine owing to their fascinating and technologically useful properties. This review presents the current progress of MXene-based materials applied in the field of electrochemical sensors. Firstly, how synthetic strategies and surface modification affect the properties of MXene was emphasized. Secondly, MXene as an electrode material for constructing electrochemical sensors based on MXene nanocomposites, especially metal nanoparticles (MNPs)/MXene, conductive polymers (CPs)/MXene, and carbon materials/MXene nanocomposites, was well discussed. Finally, the challenges and outlooks in this field with possible solutions and future opportunities are discussed.

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酚醛树脂/Ti3C2TxMXene导电复合材料制备与性能

通过氢氟酸溶液刻蚀Ti3AlC2 MAX粉末制得Ti3C2TxMXene纳米片。然后,采用溶液共混的方法制备了酚醛树脂/Ti3C2TxMXene导电复合材料。通过X射线衍射、扫描电子显微镜等手段对其结构、微观形貌及性能进行表征。结果表明:Ti3C2TxMXene纳米片均匀分散在酚醛树脂里面,形成良好的导电通路。探讨Ti3C2TxMXene纳米片的用量对复合材料的导电性能和力学性能的影响。结果表明:酚醛树脂/Ti3C2TxMXene导电复合材料的电导率,冲击强度和拉伸强度随Ti3C2TxMXene纳米片含量的增加而逐渐增加;当Ti3C2TxMXene纳米片的含量为1.2%时,酚醛树脂/Ti3C2TxMXene导电复合材料的综合性能最优,此时酚醛树脂/Ti3C2TxMXene导电复合材料的电导率为4.36×104 S/m,冲击强度和弯曲强度分别为23.9 kJ/m2和65.9 MPa。     

A facile pot synthesis of (Ti3AlC2) MAX phase and its derived MXene (Ti3C2Tx)

Various processing techniques reported in the literature for synthesizing the Ti₃AlC₂ MAX phase involve high calcination temperature, expensive equipment, and inert environmental requirement. Here, we report a cost-effective, solid-state, single-step synthesis route of the Ti₃AlC₂ MAX phase. Optimizing the stoichiometry of the precursors and controlling the thermal treatment, the desired MAX phase has been attained, as confirmed by XRD analysis. Further, Ti₃C₂T_x (where, T_x: O, OH, F functional groups) MXene was prepared from this one-pot synthesized MAX phase. FESEM, TEM, and Raman spectroscopy were used to ensure that the hexagonal structure of the MAX phase was retained in as-synthesized MXene. Further, XPS was employed to detect the presence of surface functional groups (-O, –OH, and –F) on the MXene surface. UV–vis spectroscopy shows a strong absorption peak in the NIR region.     

三元层状结构MAX相陶瓷材料的制备技术及其研究发展现状和发展趋势

三元层状结构陶瓷材料主要是指M_n+1AX_n相,三元层状结构MAX相陶瓷材料具有金属的特性还具有陶瓷的特性,三元层状结构MAX相陶瓷材料具有较高的力学性能,良好的耐磨损性能和良好的耐腐蚀性能,并具有良好的抗高温氧化性能等,还具有良好的可加工性能。三元层状结构MAX相陶瓷材料主要有Ti₃SiC₂,Ti₄SiC₃,Ti₃AlC₂,Ti₂AlC,Ti₄AlN₃和Ti₂AlN等。本文主要叙述三元层状结构MAX相陶瓷材料的制备技术,物相组成,显微结构,力学性能和耐磨损性能,耐腐蚀性能和抗高温氧化性能以及其他性能等。并叙述三元层状结构MAX相陶瓷材料的研究发展现状和发展趋势。并对三元层状结构MAX相陶瓷材料的未来研究发展趋势和发展方向进行分析和预测。     

Advancements in MXene-Polymer composites for various biomedical applications

2D materials have brought about significant technological advancements in the field of biomaterials. ‘MXene’, a ceramic-based 2D nanomaterial, is comprised of transition metal carbides, nitrides, and carbonitrides having a planar structure educed from a ceramic ‘MAX’ phase by etching out ‘A’ from it, has emerged to surpass drawbacks of conventional biomaterials. In spite of their substantial properties like large surface area, biocompatibility, hydrophilicity, metallic conductivity, and size tunability, the use of MXene is restricted in biomedical applications due of its poor stability in physiological environments, lack of sustained and controlled drug release, and low biodegradability, and these limitations lead to the notion of adopting MXene/Polymer nanocomposites. The availability of functional groups on the surface of MXenes enables polymer functionalization. These polymers functionalized MXene nanocomposites exhibit high photothermal conversion efficiency, selectivity, and stimuli-responsiveness towards malignant cells, electron sensitivity, higher antibacterial properties, and the like. This review emphasizes the innovative exemplars of polymer functionalized MXene composites for the burgeoning biomedical applications, which include controlled and sustained drug delivery, antibacterial activity, photothermal cancer therapy, unambiguous biosensing, contrast-enhanced diagnostic imaging, and bone regeneration.     

Synthesis and characterization of layered Nb2C MXene/ZnS nanocomposites for highly selective electrochemical sensing of dopamine

MXenes, due to their exceptional properties, are tagged as materials of future in the field of two dimensional (2D) materials. Niobium carbide (Nb₂C) is an important member of MXene family having vast application in the field of lithium ion batteries and supercapacitors. However, its applications in the field of sensing have not been explored yet. This research work reports the synthesis and application of Nb₂C/ZnS nanocomposite for the sensing of dopamine (DA) for the first time. The etching of Nb₂C from parent MAX phase (Nb₂AlC) was performed at 55 °C. The application of Nb₂C electrode for the electrochemical sensing of DA was employed through differential pulse voltammetry (DPV). Zinc sulphide (ZnS) nanoparticles were synthesized hydrothermally to enhance the electrochemical properties of Nb₂C. The characterization of these prepared samples was done with the help XRD, SEM, EDS, and of FTIR spectroscopy. The MXene-ZnS nanocomposite modified glassy carbon electrode (GCE) proved to be a very effective electrode material to detect dopamine electrochemically with a wide linear detection range of 0.09–0.82 mM, a very low detection limit of 1.39 μM and excellent sensitivity of 12.1 μAμM^-1. The modified glassy carbon electrode also proved to be exceptionally selective towards dopamine in the presence of interfering agents like ascorbic acid, citric acid and glucose.     

Synthesis of Ti3C2Fx MXene with controllable fluorination by electrochemical etching for lithium-ion batteries applications

Ti₃C₂T_x MXene has attracted remarkable attention due to its promising applications in energy storage and sensors. However, traditional MXene preparation methods used HF as etchant, which was highly toxic and harmful to human and environment. Moreover, the aqueous etchants will also result in the combination of OH, O and F groups on the surfaces, making it difficult to control the varieties and contents of the surface terminations. In this paper, a green and mild electrochemical exfoliation method was proposed to synthesize Ti₃C₂F_x and synchronously control its fluorination degree on the surface. A non-aqueous ionic liquid, [BMIM][PF₆]-based solution was used as electrolyte. The as-prepared Ti₃C₂F_x was fluorinated with the CF and TiF₃ groups, which were electrochemically active and contributed to the excellent cycling stability of the MXene anode-based Li-ion batteries. These findings provided a facile strategy to prepare MXene materials and dope MXene with tailored property for MXene-based energy devices applications.